External cardiac pacer with separable generating and power-probe units

ABSTRACT

A portable, self-powered, battery operated cardiac pacer comprising a removable plug-in battery and probe package and a main stimulator package, in which the stimulator, when electrically connected with the battery and probe package, will permit the cardiac surgeon to insert the negative probe lead needle into the heart muscle and to insert the positive probe lead needle into the subcutaneous tissue of the heart muscle as a ground, whereupon, in response to a predetermined timed pulse ratio selection, an abrupt short duration pulse is delivered to the heart through the positive probe. This pacer unit has a distinct advantage in that it is readily available for use in open heart procedures for instantaneous pacing either while on bypass or immediately coming off cardiopulmonary bypass when the inherent heart rate may be too slow to either sustain an adequate cardiac output of the slow rate may be associated with bradyarrhythmias. The myocardial, or heart muscle, position of the needle electrode results in a lower stimulation threshold.

United States Patent 1191 Harris et a1.

[451 Apr. 30, 1974 [22] Filed:

[ 1 EXTERNAL CARDIAC PACER WITH SEPARABLE GENERATING AND POWER-PROBEUNITS [73] Assignee: Concept, Inc., St. Petersburg, Fla.

Aug. 16, 1971 [21] Appl. No.: 171,847

[52] US. Cl 128/419 P, 128/422 [51] Int. Cl A6ln 1/36 [58] Field ofSearch 128/4 11213 128/419 P, 419 R, 419 s, 421, 422, 423, 404, 405,406, 410, 420, 2.1 R, 303.13, 172.1,

[56] References Cited UNITED STATES PATENTS 1,913,595 6/1933 Hyman eta1. 128/419 P 666,431 l/l90l Mead 128/424 3,078,850 2/1963 Schein etal.... 128/419 P 3,667,477 6 1972 Susset et a1. 128/419 E FOREIGNPATENTS OR APPLICATIONS 1,469.132 l/l967 France 128/419 P PrimaryExaminer-William E. Kamm Attorney, Agent, or Firm-Arthur H. Van HornABSTRACT A portable, self-powered, battery operated cardiac pacercomprising a removable plug-in battery and probe package and a mainstimulator package, in

I 9 which the stimulator, when electrically connected with the batteryand probe package, will permit the cardiac surgeon to insert thenegative probe lead needle into the heart muscle and to insert thepositive probe lead needle into the subcutaneous tissue of the heartmuscle as a ground, whereupon, in response to a predetermined timedpulse ratio selection, an abrupt short duration pulse is delivered tothe heart through the positive probe. This pacer unit has a distinctadvantage in that it is readily available for use in open heartprocedures for instantaneous pacing either while on bypass orimmediately coming off cardiopulmonary bypass when the inherent heartrate may be too slow to either sustain an adequate cardiac output of theslow rate may be associated with bradyarrhythmias. The myocardial, orheart muscle, position of the needle electrode results in a lowerstimulation threshold.

4 Claims, 3 Drawing Figures EXTERNAL CARDIAC PACER WITH SEPARABLEGENERATING AND POWER-PROBE UNITS NATURE AND OBJECTS OF THE INVENTIONsirablefor use not only in cardiac surgery but, with appropriate probesand modifications, may be used effectively for cardiac arrhythmilatreatment.

The interconnected units provide an effective and easily availablecardiac pacing means which is safe in use and which assures the cardiacsurgeon that the heart muscle will contract efficiently immediatelyafter discontinuing the oxygenator during open heart surgery. At thistime, the negative lead probe is inserted into the heart muscle and thepositive lead probe is inserted into the subcutaneous tissue of theheart muscle as a ground, thus imposing a potential and stimulatingpulse of appropriate amplitude and duration to activate the heartmuscle.

, THE DRAWING DESCRIPTION The battery and probe package as viewed inFIG. 1 consists of a cylindrical battery casing 1 of dielectricmaterial, closed at one end and in which one or more serially connectedbattery cells 2 are carried. Positive and negative insulated conductors3 and 4, respectively, are connected at one end to the positiveandnegative terminals of the battery unit and to receptacle contacts Sand 6carried in the female coupling member 7. mounted in the opposite end ofthe casing 1.

Insulated probe leads 8 and 9 are electrically connected at one end toprobe needles l0 and 11, respectively, through insulated respectivefinger grips l2, and to receptacle contacts 13 and -14 carried in themale coupling member 15.

The battery power source indicated at 1 and the pulse probe leads 8 and9'andprobe needles l0 and 11 are preferably packaged together in asterilized disposable package (not shown) and together with the mainstimulator 16 package, constitute a compact combination, readilyavailable for use by the operating surgeon. The main stimulator package16 is suitable for repeated use.

The main stimulator package consists of resistors R and R and R togetherwith Capacitor C, transistor T and the audio monitor and wave shapingspeakerinductor S.

I In use, the battery and probe package 1 is plugged into the stimulatorpackage 16, as illustrated in FIG. 3, with the on-off switch 17 inclosed position, the battery imposes a potential on transistor T andsimultaneously energizes the transistor emitter through resistors R andR, and capacitor C. As voltage on capacitor C builds up through R andRv, the emitter of transistor T becomes sufficiently positive to causetransistor T to become conductive, thereby discharging C through T. Thetime required for this to occur has been determined by the values of R,R and C and is a function of the desired or predetermined pulserepitition rate. In this manner, when T becomes conductive andconsequently C dischargesan abrupt, short duration pulse appears acrossthe speaker-inductor S giving an audible signal or indication that theinstrument is functioning.

Resistor R is a limiting resistor to prevent damage to transistor T inthe event the instrument operator inadvertently short circuits theprobes 10 and 11.

In use, during which the negative probe needle 10 is inserted into theheart muscle and the positive probe needle 11 is inserted into thesurrounding tissue, the stimulating pulse of appropriate amplitude andduration which is evidenced across the speaker-inductor S, is conductedinto resistor R to activate heart activity at the desired constant rate,say beats per minute.

The unit has distinct advantage in that it is readily available for allopen heart procedures for instantaneous pacing either while on bypass orimmediately coming off cardiopulmonary bypass when the inherent heartrate may be too slow to either sustain an adequate cardiac output or theslow rate may be associated with bradyarrhythmias. The myocardialposition of needle electrode results in a lower stimulation threshold.The electrodes are left in place until all coagulation is completed byuse of the electrocautery. At this time, pacing wires may then be sewnto the epicardial surface for use in the immediate postoperative periodas the needle electrodes are withdrawn. To our knowledge, the onlyavailable units at this time are the standard ventricular pacing wireswhich require suturing to the epicardium. The exposed surface of thewires may provide an electrical hazard because of possible contact withthe electrocautery. The wires must be hooked to an intermediaryconnection before they are attached to the battery source outside of thesterile field; This procedure requires a prolonged period of time ascontrasted with the use of the present invention which is of simpleconstruction, safe, inexpensive and has reliable performance.

We claim:

1. A portable, self-powered, battery operated cardiac pacer comprising,in combination, of a pair of complementary interconnecting unitscomprising a disposable battery and probe package, and a stimulatorpackage electrically and removably interconnectable one with the other,said probe package containing a battery casing, a source of batteryenery in said casing, insulated positive and negative probe conductorsextending from said casing, plug-in terminals in one end of said casingelectrically connected with the respective probe conductors at one endthereof and with said source, a probe needle electrically connected toeach of said conductors, respectively, said stimulator packagecomprising means for electrical interconnection with said terminals,pulse generator means connected to said interconnecting means forgenerating and delivering a potential through and to said conductors andsaid probes in the form of a heart stimulating pulse to the heart musclewhen said battery and said packages are electrically interconnected,said pulse generator means 3 comprising a unijunction pulse generator,said probes being oppositely charged such that when said probes areapplied to the heart, said probes develop an electrical potentialtherebetween to activate the heart muscle.

2. The invention defined in claim 1 in which is included means to selectthe repetitive rate of heart stimulating pulse output of said stimulatorpackage.

3. A portable cardiac pacer comprising a casing, a source of batterypower within said casing, plug-in terminals in said casing, certain ofsaid terminals having electrical connection with the terminals of saidbattery power source, a pair of probe conductors having electricalconnection with certain of said plug-in terminals, a pair of probeneedles each having electrical connection with one of said probeconductors, a stimulation unit pulse generator means housed within saidunit for generating and discharging a pulse potential, said pulsegenerator means comprising a unijunction pulse generator, plug-interminals in said unit for electrical interconnection with therespective plug-in terminals carried in said battery power casing todeliver battery power to said pulse generating means and to deliver thegenerated pulse rate to and through said probe needles, when therespective plug-in terminals are electrically interconnected to developand electrical potential between said probe needles to activate theheart muscle.

4. The invention defined in claim 3 including means in said stimulatorunit for selecting the pulse repetitive rate delivered to and throughone of said probe needles inserted into the subcutaneous tissue of theheart muscle and the other of said probe needles is inserted into theheart muscle.

.fUNITE-D STATES PATENT OFFICE CERTIFICATEQE CORRECTION Dated April 51974 Patent No. 3,807,191

Paul 1). llarris et a1. Inventor(s) It is certifiedthat error appearsinthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

Abstract line 10, delete "ratio" and insert rate Column 2, line 54,delete "enery" and insert energy Eolumn 4, line 8; delete "and" andinsert an Signed and sealed this 8th day of Qctober 1974.,

(SEAL) Attest:

McCOY M. GIBSON .JR. 0. MARSHALL DANN Attesting Officer Commissioner ofPatents FORM Po-mso (10-69) USCOMM'DC eoan'peg U s GUVERNMENY PRNTINQDFFKZE:

1. A portable, self-powered, battery operated cardiac pacer comprising,in combination, of a pair of complementary interconnecting unitscomprising a disposable battery and probe package, and a stimulatorpackage electrically and removably interconnectable one with the other,said probe package containing a battery casing, a source of batteryenery in said casing, insulated positive and negative probe conductorsextending from said casing, plug-in terminals in one end of said casingelectrically connected with the respective probe conductors at one endthereof and with said source, a probe needle electrically connected toeach of said conductors, respectively, said stimulator packagecomprising means foR electrical interconnection with said terminals,pulse generator means connected to said interconnecting means forgenerating and delivering a potential through and to said conductors andsaid probes in the form of a heart stimulating pulse to the heart musclewhen said battery and said packages are electrically interconnected,said pulse generator means comprising a unijunction pulse generator,said probes being oppositely charged such that when said probes areapplied to the heart, said probes develop an electrical potentialtherebetween to activate the heart muscle.
 2. The invention defined inclaim 1 in which is included means to select the repetitive rate ofheart stimulating pulse output of said stimulator package.
 3. A portablecardiac pacer comprising a casing, a source of battery power within saidcasing, plug-in terminals in said casing, certain of said terminalshaving electrical connection with the terminals of said battery powersource, a pair of probe conductors having electrical connection withcertain of said plug-in terminals, a pair of probe needles each havingelectrical connection with one of said probe conductors, a stimulationunit pulse generator means housed within said unit for generating anddischarging a pulse potential, said pulse generator means comprising aunijunction pulse generator, plug-in terminals in said unit forelectrical interconnection with the respective plug-in terminals carriedin said battery power casing to deliver battery power to said pulsegenerating means and to deliver the generated pulse rate to and throughsaid probe needles, when the respective plug-in terminals areelectrically interconnected to develop and electrical potential betweensaid probe needles to activate the heart muscle.
 4. The inventiondefined in claim 3 including means in said stimulator unit for selectingthe pulse repetitive rate delivered to and through one of said probeneedles inserted into the subcutaneous tissue of the heart muscle andthe other of said probe needles is inserted into the heart muscle.